An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, this goal has lead to decreasing track width in magnetic tapes, and increasing track density in magnetic tape heads. Similarly, for disk storage systems, this goal has lead to decreasing track width in magnetic disks, and increasing track density in magnetic disk heads. As track density in tape and disk heads increases, so does the need for precise processing and critical dimension control of recording elements and/or read elements disposed in the tape and disk heads.
Prior recording elements include magnetic poles that comprise nickel-iron alloys, such as permalloy, and are made using electroplating manufacturing methods. While electroplating provides good dimensional control, the resultant poles suffer from at least two problems. First, such poles have low resistivity values, and, thus, are not well suited for high frequency applications. Second, the poles are relatively soft, which results in increased pole tip recession.
More recently, poles have been made of alloys, such as cobalt-zirconium-tantalum, sputtered iron-nitride and sputtered nickel-iron-nitride, that are subjected to subtractive processing methods, such as wet chemical etching and electrochemical etching. These alloys, however, demonstrate different etching characteristics depending upon the material of underlying layers. Consequently, it is difficult to achieve precise dimensional control.
Prior read elements include a read structure sandwiched between top and bottom shields. The shields are made of a magnetic material such as ferrite, and the top shield is typically glued to the top of the read structure. With such a construction, it is difficult to achieve precise dimensional control.
Other prior read elements include shields made of nickel-iron alloys. While nickel-iron alloys provide good shielding properties, these materials wear excessively and, therefore, limit head life.